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If you're social, this is definitely the place to stay after halls. The only downside are the buses, but public transport is always easy to blame in all fairness. If you want to focus on uni, its activities, work and to avoid the bus, then stay closer in Canley.
Leamington Spa is a very nice city. It feels very studenty and you always see some of your friends just going in the city. Moreover, everything is close to eachother which makes it easy to live and enjoy the student atmosphere.